Sheep shearing machine



Sept. 15, 1942. P. J. Mus`oLF. 2,296,236

l SHEEP SHEARING MACHINE Filed Apri; ,25, 1941 Patented Sept. 15, 1942 SHEEP A SHEARING MACHINE Paul J. Musolf', Chicago, Ill., assigner to Chicago Flexible Shaft Company,A Chicago, Ill., a corporation of Illinois application Api-i123, 1941, serial Nc. 38ans 16 claims.' (01; ca -2,21)

This invention relates to sheep shearing machine hand pieces of a type well known in the art. The invention has more particular reference to the construction and arrangement of the driving fork, the tension applying means., and the yoke forks through which the driving and tension forces are applied to the cutter prongs.

The problem of attaining smooth, balanced cutting under all working conditions has confronted this art for manyiyears; and the primary object of` the present invention is to provide an improved structure as a solution to the problem. The` invention aims to attain equal` application of pressure to the cutter prongs through means of the yoke forks to thereby improve the cutting efficiency. To this end the invention contemplates certain structural essentials whereby to obtain substantially equal pressure one each of the cutter prongs and thereby avoid the undesirable effects ofV unbalanced cutting. To this end Iv have provided a structure wherein the radial distances from` the center of oscillation of the driving fork to the individual tips of the fork yokes at their contact with the cutter shall be maintained constant, thus avoiding variations in such radial distances inherent in prior devices. I have further provided a structure wherein optimum pressure forces are applied to the cutter so as to avoid any tendency of the cutter to tilt dur-ing the rapid oscillation, as explained hereinafter.

Another object is to provide improved fork yokcs which contribute to the object above stated.

Another object is to improve the fork yokes by the provision of novel structure enabling larger bearing surfaces and longer litt.

Another object is to provide an improved tension pin bearing cup whereby to carry the length of the fork yoke bearings much farther` back, giving improved leverage for the forces applied through the fork yokes.

Other objects and` attendant advantages will be appreciated by those skilled in the art as the` invention becomes better understood by reierence to thefollowing description when considered in connection with the accompanying drawing, in which- Figure 1 is a vertical section through a sheepV endviews, respectively, of the left hand fork yoke;`

Fig. 8 is a cross section taken on the section line 8-3 of Fig. Li;

Fig. 9 is a bottom view of the driving fork and the fork yokes in operative relation; and

Figs. 10 and 11 are detail sections taken substantially on the section lines Iii-Eil of Fig. 2 and I!.il of. Fig. 9, respectively.

In illustrating my invention I have shown a ing used to designate the parts generally. The

parts described are of well knownV construction and my invention deals primarily with a novel organization of these parts and with improveI ments inthe driving fork and the fork yokes.

According to my invention. the lower bearing end ofthe inclined tension pin 23is preferably of partially spherical form 24 to lit in a bearing ,socket located relatively low on the driving fork with the center of the bearing end approximately intersecting a plane passing through the center of the bearing member IEV and the fork yoke tips at their contact with the cutter, this plane being designated A-A in Fig. 1. The fork yokes are so shaped and arranged in coaction with the-driving Figs. 4, 5, 6 and 7 are top, side, bottom and. 55

fork asto locate the axis oi rotation B-B (Figs. 2 and 10) of eachfork yoke coplanar with the plane AA. In the present embodiment the fork yokes are designed for a three prong cutter and the axes B-B are radial with respect to the vertical axis of the driving fork center Iii, but it will be understood that the invention may be applied with a four prong cutter and .said axes i need not necessarily be in said radial relation.

I prefer, however, and my invention contemplates as one of its objects, that the fork yokes shall be shaped to lprovide comparatively long Shanks each having bearing portions 25 and 26 at `opposite ends, 25 being a half-round section of comparatively large diameterY and 2t a pin of annular cro-ss section and reduced diameter. The driving fork is provided on its underside with open bearing sockets 21 complemental to the semi-circular bearings 25 and annular bearings 28 for the bearing pins 26. Each yoke portion 29 (Fig, intermediate the bearing portions 21 and 28 is preferably relieved from the yoke shank. The fork yokes I1 and I8 are left and right hand respectively, each having its outer branch 3l provided with a cone point 32 for thrust and drive transmitting engagement in a complemental cone bore in the cutter and having its inner branch 33 provided with a thrust point 34. The fork yokes are proportioned so that the inner branches share the tension pressure applied through the points 34 to the center prong 35 of the cutter and the outer branches individually transmit both tension thrust and drive transmitting thrust through the cone points 32 to the outer prongs 36 of the cutter, the arrangement being such that the combined tension pressure of the inner branches is equal to the tension pressure applied individually by each outer branch. The yoke Shanks are free to have pivotal movement about their respective axes B-B to function in equal distribution of the applied tension forces to the respective cutter prongs. Suitable means is provided for releasably retaining the fork yokes in operative engagement with the driving fork, such as a spring member 31 fastening to the underside of the driving fork by a screw 38 andhaving spring arms 4| pressed against the flattened underside of the fork yokes in front of stop projections 39 thereon.

It will be observed that in contradistinction from the prior art the yoke forks are so designed as to enable the axis of rotation B-B of each fork to be brought down to the plane A-A in which the forces are applied, and that this is accomplished Without interference with the cutter or the handpiece housing at any position, even with the cutter reduced to its smallest dimension by Wear or sharpening. Also, the semi-circular cross section of the yoke bodies enables the use of comparatively large diameter bearings, giving larger bearing surface and longer life. My invention also provides greatly improved leverage for the forces applied through the fork yoke, the distances C and D, Fig. 5, being about three to one as compared to about one to one in the prior art. This also makes for less tendency of the yoke structure to spring or deflect by reducing the bending stress against the fork yoke as a result` of said three to one ratio. In the present embodiment the length of the fork yoke shank is further permitted by employing a bearing 25 of novel form consisting of a cup-shaped member 42. This cup bearing is so shaped and arranged that theball point 24 on the tension pin seats in the small end of the taper at the lower point of the cup and the Wide end of the cup member is confined by a taper fit in the driving fork.

Referring now to the principle of operation and the advantages of my invention: As stated, one of the main objects of the invention is to obtain equal pressure on each of the cutter prongs of which there are three in the present embodiment. My improvements may, however, be applied to a four prong cutter, in which case the fork arms would be properly proportioned for distribution of the pressure. Attention is now directed to the arrangement of the parts so that the longitudinal pivot axes B--B of the fork yokesare disposed in the plane A-A, which preferably passes through the center of the bearing for the driving fork, the center of the tension pin bearing in the driving fork, and the yoke tips at their point of contact with the cutter prongs. This provides a new relationship of parts and gives new results. It will be observed that the radial distances from the center of oscillation of the driving fork (the center of the mounting IS) to the individual yoke tips is necessarily a factor in determining the pressures applied to the cutter prongs; consequently, if such radial distances should vary at different stages in the operation the applied pressure would also vary. It will be observed that the degree to which the rotative aires of the fork yokes of the prior art pass above the rotative center l5 of the driving fork constitutes an initial tendency toward the changing of this radial distance in addition to the change due to the normal inclination resulting from wear of the cutter. By causing the rotative axes B-B of the fork yokes to be positioned coplanar with the plane A-A there is no initial inclination of the fork yokes beyond the minimum consistent with the lowest practicable positioning of the pivot point I5 of the driving fork. Thus, variation in radial distances referred to is held to the minimum. This will be evident when it is considered that the greater this initial angle or inclination the more rapid will be the radial distance change as a consequence of normal wear and grinding of the cutter. Variation of said radial distance will produce unequal pressure against the cutter prongs which will result in unbalanced cutting, that is, more pressure against the center prong than against the outer prongs. Such unbalanced cutting tends to cause the prong with the lesser pressure to tear the wool as distinguished from a clean shearing cut. It will be further observed' that if the lower center of the tension pin is elevated above a line drawn through the center of oscillation of the driving fork and the contact points of the yoke tips against the top of the cutter prongs (in other words, the plane A-A) there would be a tendency for the tension pin to lag behind the movement of the driving fork and produce a tendency to tip the driving fork away from the direction of motion. This would result in a release of pressure on the leading cutter prong and an increase of pressure on the trailing prong. This condition is avoided by my present invention in which the lower bearing point or lower center of the tension pin is placed on the line or plane A-A above described. This avoids the tipping tendency and further makes for smooth, balanced cutting. It will also be observed that the semi-circular form of bearings for the fork yokes provide a practical structure enabling the axis of rotation of each fork yoke to be lowered from the prior art inclinations to the plane A-A, in which the forces are applied. This structure also enables the use of larger diameter bearings and consequently larger bearing surface, which gives longer life. Another advantage of my invention is that the bearing support for the fork yokes is carried much farther back than heretofore, giving greatly improved leverage for the forces applied through the fork yokes. Still another advantage is that the yoke forks are maintained in a relatively low position on the driving fork so as to oifer the least resistance to the wool. This further promotes smoothness in shearing.

While I have shown a particular embodiment of my invention, it will be understood that I do not wish to be limited thereto since many modifications may be made, and I therefore contemplate by the appended claims to cover any such modifications as fall within the true spirit and scope of my invention.

I claim: 1.(A sheep shearing handpiece of 'the type having an inclined downwardly pressed tension pinv on the handpiece rearwardly of said thrustl bear-` ing and having at its forward end fork yokes which have tip contacts with the cutter, each fork yoke beingmounted on the driving fork with capacity for pivotal movement about an axis extending lengthwise of the drivingy fork, the parts being so constructed and arranged that a plane common to said yoke axes and intersecting said tip contacts and the center of the driving fork pivot bearing also intersects approxi-y mately the center of the ball thrust bearing.

2. A sheep shearing machine handpiece having a combv and a cut-ter, a driving fork having intermediate its ends, a pivot mounting on the handpiece, fork yokes mounted on the forward lendV of the driving fork and having tip contacts with the cutter, a downwardly pressed tension pin having a spherical lower end fitted in a socket bearing in the driving fork intermediate the fork yokes and said pivot bearing to impose tension between the comb and the cutter, the parts being so constructed and arranged that a plane intersecting said tip contacts and the center of the driving fork bearing also intersects approximately the center of the ball and socket thrust bearing at the lower end of the tension pin.

3. A sheep shearing machine handpiece as set forth in claim 2 in which each fork yoke has a shank approximately semi-circular in cross section providing a semi-circular tcp bearing portion of relatively large diameter, and the driving fork has bearing sockets complemental to the semi-circular bearing portions for coaction therewith, the semi-circular form of said bearings and shanks permitting location of the fork yokes and the driving fork in close proximity to the cutter.

4. A sheep shearing machine handpiece having fork yokes through which the cutter driving and tensioning forces are applied, each yoke having a main bearing portion substantially semi-circular in cross section, said portion providing a substantially semi-circular top bearing surface and a substantially fiat underside.

5. A sheep shearing machine handpiece having fork yokes as set forth in claim 4. in which the semi-circular bearing portion is located at the front end of the shank and is of relatively large diameter and the shank is provided at its rear end with a cylindrical bearing pin of relatively small diameter coaxial with the axis of its said semi-circular portion.

6. A sheep shearing machine handpiece having a comb and a cutter, a driving fork, fork yokes operative between the driving fork and the cutter for transmitting the drive and tension forces, the driving fork having semi-circular bearing sockets in said underside opening at the bottom for the reception. of the fork yokes, each fork yoke having a shank provided with a top bearing portion semi-circular in cross section adapted to nt in one of said driving fork bearing sockets, the underside of said semi-circular bearing portions of the driving fork and the fork yokes being substantially coplanar. and the parts being constructed and arranged so that said coplanar underside is in close proximity to the cutter.

7. AV sheep shearing machine handpiece asset forth in claim 6, including a spring clip `fastened to the underside ofthe driving fork and shaped to coact with the iiat undersides of the fork` yoke shanksY to normally retain the fork yokes in operative relation to the driving fork.

8. A fork. yoke for a sheep shearing machine hand. piece comprising a shank having forked armsat the front end thereof, each forked arm having a contact tip at its forward end adapted for coaction with the cutter of the handpiece,

the forward end portion of the shank being substantially semi-circular in cross section at its top endandhaving a` substantially flat underside coplanar with the underside of the forked arms of the yoke.

9. A fork yoke for a sheep shearing machine handpiece as set forth in claim 8, in which the shank has a cylindrical rear end portion providing a full round bearing of relatively small diameter coaxial with the axis of the semi-circular front bearing portion and in which the front and rear bearing portions are separated by a tapered intermediate portion.

10i A fork yoke for a sheep shearing machine handpieceas set forth in claim- 8, in which the shank has a cylindrical rear end portion providing a full round bearing of relatively small diameter coaxial with the axis of the semi-circular front bearing portion and in which the front and rear bearing portions are separated by a tapered intermediate portion, the overall length of the semi-circular bearing potrion and the tapered portion of the shank being approximately twice the effective length of the yoke arms.

1l. In a sheep shearing machine handpiece, a driving fork having a pivot mounting, fork yokes having shanks seated in bearings on the forward portion of the driving yoke forward of said pivot mounting, the fork yokes coacting with the cutter for applying the driving and tensioning forces, each fork yoke shank being rotative about an axis extending lengthwise of the driving fork, a downwardly pressed tension pin having a spherical lower end for applying tension to the driving fork and through the fork yokes to the cutter, and a bearing cup on the driving fork intermediate the rear end portions of the fork yoke shanks and having a spherical socket in which the spherical end of the tension pin is seated in thrust engagement, the cup member having an annular wall portion diverging upwardly from its spherical end providing an annular exterior tapered surface extending upwardly substantially beyond the spherical socket portion, the driving fork having a tapered socket in which the tapered portion of the cup member is pressed to position the center of the tension pin thrust bearing relatively low on the driving fork.

12. A sheep shearing machine handpiece as set forth in claim 11 in which the fork yoke axes converge rearwardly and intersect approximately at the pivot mounting of the driving fork, and in which the shanks of the fork yokes extend rearwardly of the tension pin cup member bearing.

13. A sheep shearing machine handpiece having a comb and a cutter, a driving fork having a pivot mounting, fork yokes operative between the driving yoke and the cutter for transmitting the drivey the driving fork having on its underside semi-circular bearing sockets with the diametrical openings of the sockets substantially coplanar with the underside of the driving fork, each fork yoke having a shank provided with a bearing portion semi-circular in cross section tting on one of the driving fork sockets with the at side of the bearing portion substantially coplanar with said underside of the driving fork, each fork yoke having tips coacting with the cutter, the pivot axes of the fork yoke shanks being substantially 4coplanar with said flat underside of the driving fork, the parts being so constructed and arranged that said fork yoke pivot axes are substantially coplanar with a plane intersecting said fork yoke tips and the center of the driving fork pivot mounting.

14. A sheep shearing machine handpiece as set .forth in claim 13 in which tension is applied to the cutter through a tension pin acting at its lower end against the driving fork at a point between the driving fork mounting and the fork yokes, the tension pin having a spherical lower end in thrust engagement with a complemental bearing socket on the driving fork, said tension pin thrust bearing being at a substantially low point on the driving fork with the center of the spherical thrust bearing substantially at a point of intersection with said plane connecting the fork yoke tips and the driving yoke mounting.

l5. The combination in a sheep shearing machine handpiece, of a comb and a cutter, a driving fork adapted to oscillate laterally on a pivot mounting, a fork yoke operative between the driving fork and the cutter for driving the cutter, the fork yoke having tip contacts with the cutter, one of which contacts transmits said drive, the fork yoke having capacity for rotative movement on the driving fork about an axis extending lengthwise thereof, said axis being coplanar with a plane intersecting said yoke tips and the center of the driving fork pivot mounting, and a tension pin applying downward pressure to the driving fork at a point intermediate its pivot mounting and its forward end, said tension being applied to a point coplanar with the plane intersecting said yoke tips and the center of the driving fork pivot mounting.

16. The combination set forth in claim 15, including a pair of fork yokes constructed and arranged as described, the fork yokes being laterally spaced apart and each having a shank provided with a half round bearing portion at its front end of relatively large diameter with the flat side at the bottom and a full round bearing portion of relatively small diameter at its rea! end, the full round portion being coaxial with the center axis of the half round portion, the overall length of said bearing portions being more than twice the effective length of the forked end of the yoke forward of the half round bearing portions,

PAUL J. MUSOLF. 

